drm/i915: Verify the engine workarounds stick on application

Read the engine workarounds back using the GPU after loading the initial
context state to verify that we are setting them correctly, and bail if
it fails.

v2: Break out the verification into its own loop

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190417075657.19456-3-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem.c

@@ -4842,6 +4842,23 @@ static void i915_gem_fini_scratch(struct drm_i915_private *i915)
 	i915_vma_unpin_and_release(&i915->gt.scratch, 0);
 }
 
+static int intel_engines_verify_workarounds(struct drm_i915_private *i915)
+{
+	struct intel_engine_cs *engine;
+	enum intel_engine_id id;
+	int err = 0;
+
+	if (!IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM))
+		return 0;
+
+	for_each_engine(engine, i915, id) {
+		if (intel_engine_verify_workarounds(engine, "load"))
+			err = -EIO;
+	}
+
+	return err;
+}
+
 int i915_gem_init(struct drm_i915_private *dev_priv)
 {
 	int ret;
@@ -4927,6 +4944,10 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 	 */
 	intel_init_clock_gating(dev_priv);
 
+	ret = intel_engines_verify_workarounds(dev_priv);
+	if (ret)
+		goto err_init_hw;
+
 	ret = __intel_engines_record_defaults(dev_priv);
 	if (ret)
 		goto err_init_hw;